Field of the Invention
The present invention relates to an image display device which forms an image using a light source and an optical modulator that modulates transmittance or reflectance of light incident from the light source per pixel according to a drive signal, and a control method of the image display device.
Description of the Related Art
Color matching functions that represent human visual characteristics related to color are known to have individual variability attributable to fluctuations caused by age and the like. CIE170-1 is proposed as a model of such a fluctuation by the International Commission on Illumination (CIE).
The existence of such individual variability sometimes causes color to appear subtly different on an image display device from person to person. As a result, there may be cases where, depending on an observer, a color does not appear to be matched even after performing color calibration for colorimetric matching with printed matter. This phenomenon is particularly prominent among display devices using light sources with a narrow spectrum as a backlight in order to expand a display color gamut.
In order to solve this problem, there is a method of reducing individual variability of the appearance of color by reproducing a color spectrum of the real world as faithfully as possible on the basis that image signals and display devices have six primary colors (Japanese Patent Application Laid-open No. 2003-141518).
Alternatively, a display device is proposed that combines a broad light source which has a broad emission spectrum and which is used when an image to be displayed has low chroma and a narrow light source which has a narrow emission spectrum and which is used when an image to be displayed has high chroma (Japanese Translation of PCT Application No. 2012-515948). The display device is designed to achieve both a reduction of individual variability in appearance of color and an expansion of a display color gamut.
In addition, a method of expanding a color gamut of a display device by simultaneously lighting, in addition to an RGB basic light source, an extended light source of a different color is proposed (Japanese Patent Application Laid-open No. 2012-47827).
Furthermore, a method of expanding a color gamut of a display device by changing an applied current value of an RGB basic light source per factice field to increase the number of colors of the light source is proposed (Japanese Patent Application Laid-open No. 2005-275204).
Moreover, an image display device is proposed which is configured such that two light sources are provided for one color of a color filter, the two light sources belong to a same color category, and two peak wavelengths that differ from each other of the two light sources both fall within a wavelength range of transmission characteristics of the color filter (Japanese Patent Application Laid-open No. 2004-138827).